Dominant contribution of Asgard archaea to eukaryogenesis

Abstract The origin of eukaryotes is one of the key problems in evolutionary biology 1,2 . The demonstration that the last eukaryotic common ancestor (LECA) already contained the mitochondrion—an endosymbiotic organelle derived from an alphaproteobacterium—and the discovery of Asgard archaea—the closest archaeal relatives of eukaryotes 3–7 —inform and constrain evolutionary scenarios of eukaryogenesis 8 . We conducted a comprehensive analysis of the origins of core eukaryotic genes tracing to the LECA within a rigorous statistical framework centred around evolutionary hypothesis testing using constrained phylogenetic trees. The results show dominant contributions of Asgard archaea to the origin of most of the…